This application is to request funding for the 2001 Gordon Research Conference on CAG triplet repeat disorders to be held in Mount Holyoke College, MA, USA, July 15-20, 2001. Two major groups of genetic neurological disorders were recently identified as unstable triplet repeat diseases. Their discovery represents the foundation of a new set of principles in genetics. One group of diseases includes fragile X, myotonic dystrophy and Friedreich's ataxia. Patients with these disorders all exhibit an expansion of triplet repeats in a non-coding sequence of the DNA genome. In the contrast, the other group of neurologic disorders exhibit expanded triplet repeats (coding for CAG bases) in the coding part of the genome, resulting in a polyglutamine tract. This latter group includes Huntington's disease, spino-cerebellar ataxia 1, 2, 3, 6 and 7, spinobulbar muscular atrophy and dentato-rubral pallido-luysian atrophy. These disorders results in a selective loss of neurons in the brain and spinal cord, with a different anatomical distribution in each disease. Although the genetic defects are established, it remains to be elucidated how the mutant gene in each case generates the specific pathogenetic process and how this leads to a characteristic anatomical pattern of changes. The identification of these mutant genes raises hopes for many affected by severe genetic disease. However, before development of novel therapies can be expected, it is necessary to better understand the disease processes. This requires a multi-disciplinary research effort with collaborative projects between scientists from diverse specialties ranging from fruit fly genetics to clinical neurology and neuropathology. This conference on CAG triplet repeat disorders will gather both young and senior, key scientists who will present provoking lectures on the cutting-edge of science. In keeping with the Gordon Research Conference format, there will be generous time allocated to both structured discussions led by peers and for informal discussions and social generous time allocated to both structured discussions led by peers and for informal discussions and social interaction. Strong emphasis is placed on training and mentoring of young scientists and time is also devoted to career issues. All participants (except speakers and discussants) will be encouraged to present posters. When participants are selected there will also be priority given to women, minorities, and persons with disabilities